The constituents of Withania somnifera / by Frederick B. Power and Arthur H. Salway.

  • Frederick Belding Power
Date:
[1911?]
Catalogue details

Licence: In copyright

Credit: The constituents of Withania somnifera / by Frederick B. Power and Arthur H. Salway. Source: Wellcome Collection.

    15/22 page 502
    to the hot mother-liquors, the greater portion of the oleo-resinous material was removed, after which a crystalline substance began to be deposited. The latter was then purified by several recrystal¬ lisations from dilute alcohol, when it was obtained in colourless, prismatic needles in an amount of 3 grams: 0'5981, dried at 110°, lost 0'0364 H20. H20 = 6*l. 0-0975* gave 0'2542 C02 and 0*0748 H20. “ C = 71T ; H = 8*5. 0-1126* „ 0*2882 C02 „ 0*0834 H20. C = 71*0; H = 8*4. 0-1136* „ 0*2968 C02 „ 0’0844 H20. C = 71*3; H = 8*2. C32H4407,2H20 requires H20 = 6*2 per cent. C32H4407 requires C = 7T1; H = 8'l per cent. The molecular weight of the substance was determined by the cryoscopic method with the following result: 0*5496*, in 31*52 nitrobenzene, gave \t= — 0'225°. M.W. = 542. C32H4407 requires M.W. = 540. No substance identical with the above compound appears to have hitherto been described. It is therefore proposed to designate the new compound somnirol, with reference to its alcoholic properties and the specific name of the plant from which it has been isolated. Somnirol, C32H43Og*OH, is very soluble in alcohol, ethyl acetate, or chloroform, only moderately soluble in benzene, and very sparingly so in ether. It crystallises from dilute alcohol with two molecules of water of crystallisation, which are expelled at 110°, but are again rapidly absorbed when the anhydrous substance is exposed to the atmosphere. The behaviour of the substance on heating is characteristic, inasmuch as it partly melts at about 155° with effervescence and immediate resolidification, and then finally fuses with evolution of gas at 205°. A determination of the optical rotatory power of somnirol gave the following result : % 0T796,* made up to 25 c.c. with chloroform, gave aD +0°30/ in a 2-dcm. tube, whence [a]D + 348°. Somnirol contains no methoxyl, and, as shown below, only one hydroxyl group. In order to obtain some further information respecting the character of the substance, a portion of it was heated with decinormal alcoholic potassium hydroxide: 02002, heated for 20 minutes, neutralised 00222 KOH. KOH = lll percent. 0*2271, heated for one hour, neutralised 0*0275 KOH. KOH = 12*1 per cent. C32II4407, to neutralise 1 mol. KOH, requires KOH = 10*4 per cent. With the object of isolating, if possible, the products of the
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